1. Field
The technology of the present, application relates to spinal corrective surgery and, more particularly to spinal fixation rods coupled to vertebral bodies having adjacent disc support extension.
2. Background
Back pain may be caused by degeneration or other deformities of an intervertebral disc (“diseased disc”). Conventionally, surgeons treat diseased discs by surgically removing the diseased disc and inserting an implant in the space vacated by the diseased disc, which implant may be bone or other biocompatible implants. The adjacent vertebrae are then immobilized relative to one another. Eventually, the adjacent vertebrae grow into one solid piece of bone.
Several techniques and systems have been developed for correcting and stabilizing the spine and facilitating fusion at various levels of the spine. In one type of system, a rod is disposed longitudinally along the length of the spine in the region of concern. The rod is arranged according to the anatomy and the correction desired. In this system, the rod is aligned along the spine and engages various vertebrae along its length. The rod engages, or more typically the parallel rods engage, the spine using fixation elements, such as, anchors attached to vertebral bodies by a bone screw.
Non-fusion options for surgically removing pain generators recently have become more prevalent. Some non-fusion technologies include distracting the intervertebral disc spate while allowing some motion. Generally, the non-fusion options have extension stops to limit the compression of the disc space, but attempt to provide more freedom of motion in flexion. Refer to the above incorporated applications U.S. patent application Ser. No. 11/128,962, titled Pedicle Screw Based Vertebral Body Stabilization Apparatus, filed May 12, 2005, and U.S. patent application Ser. No. 11/383,326, titled Pedicle Screw Based Vertebral Body Stabilization Apparatus, filed May 15, 2006, for more information on non-fusion pedicle based systems.
Limiting the range of motion of a spinal segment, whether immobilizing the segment (fusion) or limiting the motion of the segment (non-fusion) can place additional stress on adjacent or proximate vertebral segment. This additional stress may accelerate or contribute to the degeneration of adjacent discs or the like. Sometimes adjacent or proximate segments may already have some degeneration or other deformity that is exasperated by the limited motion of the adjacent or proximate segment.
Thus, against this background, it would be desirous to develop a technology that provides some support for adjacent or proximate spinal segments to inhibit any or additional degeneration.